MULTI-MEGABAR PRESSURE AND SUPER-DENSE MATERIALS CREATED BY LASER-INDUCED MICRO-EXPLOSION INSIDE OF TRANSPARENT SOLID

摘要

Extremely high pressure (~10 Tpa) and temperature (5×105 K) have been produced using a single laser pulse (~100 nJ, 800 nm, 200 fs) focused inside transparent dielectrics. The laser pulse of intensity over 0.1 PW/cm2 converts a material within the absorption volume of ~0.15 μm3 into plasma in a few femtoseconds. A pressure of ~10 Tpa, far exceeding the strength of any material builds up to the end of the pulse generating strong shock and rarefaction waves. This results in the formation of a nano-void surrounded by a shell of shock-compressed material. In sapphire, the compressed shell revealed that it has a density 1.14 times of the initial one and increased chemical reactivity. The unique conditions: extreme pressure and temperature at record high heating and cooling rates become available in a well-controlled laboratory environment.